Signal class for button click

[davidshumway]

Hello. Great project, thank you.

Regarding a game that is in project: https://github.com/Roland00111/Trumpocalypse.

Is it possible to describe the functionality for the Signal class? All that is necessary is to pass in a callback_function to an instance of a Button class for the onclick method. For the time being the idea for a workaround is to just alter Button to take a callback function as a parameter. Then call the callback function in the mouse_up function.